I have an '82 F100 SWB Stepside, which is oddly equipped, it has the big ol' six, but the rest of the drivetrain is odd, a SROD 4 speed, and a 3.08 geared 9" and according to the tag on the door, it came with 235/60R15 tires on 8" rims(neither of wich are still on it,)it appears that this truck came equipped for speed and better handling, but, it has a normal truck suspension, and if I had not looked at the door plate, I would just have thought this truck was a F100S, as it has nothing special on it, not even carpet. I don't know about it's quarter mile time, but, it goes, I can get 50 out of it in 1st, 70 in 2nd, 90 in 3rd, and I haven't pushed it past 100 in high(2500 rpm.)

Anyone have any clues?

 

What does the door plate have that leads you to believe this isn't something someone modified?